Stems square, with opposite branches, 15-40cm long, 2-4mm in diameter; externally purplish-brown or pale green, the angular regions pubescent, internodes 2-5cm long; texture fragile, fracture white, pith hollowed. Leaves opposite, short petioled, lamina crumpled and rolled, when whole, broadly lanceolate, long-elliptical or ovate, 2-8cm long, 103cm wide; the upper surface dark green and the lower surface greyish-green, sparsely pubescent, bearing concave dotted glandular scales. Verticillaster axillary, calyx campanulate, with five terminal teeth, corolla pale purple. Odour, characteristic and aromatic after rubbing; taste, pungent and cool.

Headache in influenza, upper respiratory infection and other epidemic febrile diseases at the initial stage; inflammation of the eye, sore throat, ulcers in the mouth; rubella measles; discomfort with feeling of distension in the chest and hypochondriac regions.

1. Dispersing evil wind-heat from superficies,

For either exterior syndrome due to wind-heat which is marked by fever with slight chill, headache and anhidrosis, or exterior syndtome of seasonal febrile disease at its beginning stage, Hera Menthae is often combined with Flos Lonicerae, Fructus Forsythiae, etc.; for high fever, with Gypsum; for syndrome of summer-heat in summer which is marked by dizziness, fever, thirsty, scanty and dark urine, with Talcum, Radix Glycyrrhizae, thirst, scanty and dark urine, with Talcum, Radix Glycyrrhizae.

2. Clearing away the evil factors in the head,brightening the eyes and soothing the throat,

For treating cold due to wind-heat or such symptoms as headache with red eyes, sore throat, etc., due to invasion of the head by wind-fire, it is combined with Herba Schizonepetae, Flos Chrysanthemi, Radix Ledebouriellae, Fructus Arctii, Radix Platycodi, Radix Glycyrrhizae, etc.

3. Promoting eruption and arresting itching

It is often combined with Fructus Forsythiae, Periostracum Cicadae, Fructus Arctii, Herba Schizone-petae, Radix Ledebouriellae, etc. for the treatment of measles with failure of letting out skin eruptions due to invasion of the superficies and muscles by wind-heat, and urticaria, pruritus, etc.

Besides, it is also indicated in depression of liver-Qi, distention and pain of the chest and hypochondriac region; for this purpose, a proper amount may be added to the other ingredients of the prescription for soothing the liver.